1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device which includes a backlight unit on a back surface of a non-self-luminous display part.
2. Description of the Related Art
For example, a liquid crystal display device is usually configured such that a backlight unit is mounted on a back surface of a liquid crystal display panel.
The liquid crystal display panel is constituted as a so-called non-self-luminous display panel where optical transmissivities of a plurality of pixels in a display region of the liquid crystal panel are controlled by driving liquid crystal. Due to such a constitution, a display image displayed by the liquid crystal display panel is formed of lights which are emitted from the backlight unit and pass through the respective pixels.
In the liquid crystal display panel, a display region is formed of a plurality of pixels arranged in a matrix array, and light shielding is provided between one pixel and other pixels which are arranged adjacent to one pixel in the left, right, upper and lower directions for every pixel. This light shielding is provided mainly for preventing a signal line arranged between the pixels from being observed with naked eyes, for preventing color mixing between the neighboring pixels, for preventing the deterioration of characteristics of a thin film transistor for pixel selection arranged in the vicinity of the signal line due to the irradiation of light to the thin film transistor and the like.
As the backlight unit, there has been known, for example, a backlight unit which is constituted of alight guide plate arranged to face a liquid crystal display panel in an opposed manner, a plurality of light emitting diodes arranged along a side surface of the light guide plate, and a reflection sheet arranged on a surface of the light guide plate on a side opposite to a liquid-crystal-display-panel side. The backlight unit having such a constitution functions as a flat light source since light emitted from the light emitting diodes propagates in the inside of the light guide plate, is reflected on the reflection sheet or the like and is irradiated from a surface of the light guide plate on the liquid-crystal-display-panel side.
Further, JP 5-150231 A discloses a technique where out of a pair of transparent substrates which forms a liquid crystal display panel, a light shielding film is formed over a polarizer mounted on an outer surface of the transparent substrate arranged on a backlight unit side, and the light shielding film is made of a material having high reflectance thus enhancing light utilization efficiency of backlight light.